Migration enhanced epitaxy (MEE) is actively examined as a process for achieving enhanced crystallinity of a semiconductor layer made of a group III-V compound in recent years (see, for example, Japanese Patent Laid-Open No. 2003-142,404: hereinafter referred to as Document 1).
Such MEE is a process that promotes an acceleration of a surface diffusion of atoms of a III-group element, and involves, for example, alternately conducting a supply of atoms of a group-III element and a supply of atoms of a group-V element. The alternative supply of atoms of different elements results in the situation, in which atoms of a group-V element is not supplied when atoms of a group-III element is supplied, so that pressure exerted to atoms of a group-III element is reduced and a surface diffusion of atoms of a group-III element is activated. This allows that atoms of a group-III element, which has been adsorbed to a growth surface, is diffused over the surface, reaching to kinks and steps formed on the growth surface. It is described that the crystalline growth in this way results in obtaining improved crystal that is derived from the crystallinity of the underlying layer.